The invention relates to a drive unit for driving a mobile machine having a hydraulic generator for working hydraulics.
Mobile machines have a drive set, for example, in the case of a mobile construction machine, an internal combustion engine or, for example, an electric motor in the case of a fork-lift truck. This drive set is used for the traction drive and can additionally provide energy for possible working hydraulics, for example for raising and lowering the forks in the case of a forklift truck and/or can be used to drive secondary appliances, for example a generator.
Drive systems in which a hydraulic pump or a hydraulic motor is arranged between an internal combustion engine and a gearbox are known, for example, from US 2006/0118346 A1. This document describes how a hydraulic hybrid system can be integrated in a vehicle. The hydraulic pump allows kinetic energy to be taken from the vehicle via the drive train, for example during braking. The energy is stored in a pressure accumulator and is emitted as required again to the drive train via the hydraulic motor. The hydraulic set, according to US 2006/0118346 A1, may be in the form of a continuously variable radial piston pump, and it is in this case used purely for the traction drive.
Furthermore, crankshaft generators are known as electrical generators from commercial vehicles. One such system is described in DE 103 51 308 A1. This relates to a vehicle axle system with a front vehicle axle, which is preferably mounted in a pendular form, for agricultural or industrial commercial vehicles, in which an electrical drive is provided for this axle, which is not driven by the internal combustion engine. In this case, an electrical crankshaft generator is arranged between the internal combustion engine and the gearbox. The electrical energy obtained from the crankshaft generator is used to drive the axle system. The electrical components for the electrically driven axle are in this case preferably fitted in a torque tube in the vehicle. The torque tube furthermore has the function of supporting the axle suspension on the frame. A concept is therefore also described here in which the energy obtained via an electrical crankshaft generator is used for the drive, in this case for a vehicle axle which is not driven by the internal combustion engine.